1. Field of the Invention
The technical field relates to a semiconductor device, a method for driving a semiconductor device, and a method for manufacturing a semiconductor device. The semiconductor device is particularly a semiconductor integrated circuit including a semiconductor element such as a transistor.
2. Description of the Related Art
A programmable logic device (PLD) is one of semiconductor integrated circuits. A PLD is an integrated circuit having an internal configuration that can be determined and altered (is reconfigurable) after manufacture (see Patent Document 1).
A PLD has the following advantages, for example, over a conventional application specific integrated circuit (ASIC): the development period can be shortened and a PLD enables flexible response to a change in design specification. Accordingly, PLDs are used in various kinds of devices.
A PLD includes, for example, a plurality of logic circuit units and a wiring between the logic circuit units. A function of the PLD can be changed by changing the circuit configuration of each of the logic circuit units or by changing the connection relation between the logic circuit units.
Further, the PLD may include a storage circuit, in which case data on the circuit configuration of each of the logic circuit units and the data on the connection relation between the logic circuit units can be stored in the storage circuit.
As the logic circuit unit, an arithmetic logic unit (ALU) is used, for example. An ALU generally consists of an arithmetic operation unit including a combination of an adder, a subtractor, and the like; a logic operation unit including a combination of an AND circuit, an OR circuit, and the like; a shift operation unit including a shift circuit; and a selector circuit that selects these units to output their outputs, such as a multiplexer.